Bump python from 3.8-slim to 3.12-slim

Bumps python from 3.8-slim to 3.12-slim.

---
updated-dependencies:
- dependency-name: python
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

development.dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.8-slim
+FROM python:3.12-slim
 
 RUN apt update && apt install curl build-essential -y
 

fly.dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.11-slim
+FROM python:3.12-slim
 
 LABEL maintainer="Zauberzeug GmbH <nicegui@zauberzeug.com>"
 

release.dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.11-slim as builder
+FROM python:3.12-slim as builder
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC \
@@ -11,7 +11,7 @@ RUN python -m pip install --upgrade pip
 
 RUN python -m pip install --upgrade libsass
 
-FROM python:3.11-slim as release
+FROM python:3.12-slim as release
 COPY --from=builder /usr/local/lib/python3.11/site-packages /usr/local/lib/python3.11/site-packages
 ARG VERSION